JP6261607B2 - Reactor for autothermal vapor dehydrogenation - Google Patents

Description

  The present invention relates to a reactor for performing autothermal gas phase dehydrogenation using a heterogeneous catalyst configured as a monolith, and a method using the reactor.

  Ceramic or metal monoliths have been established as catalyst carriers for precious metal catalysts in the field of mobile and stationary exhaust gas cleaning. The passage can reduce the flow resistance of the flow, while at the same time realizing that the gaseous reaction medium contacts the outer surface of the catalyst evenly. This is an advantage over irregular aggregates, which cause large pressure losses due to innumerable deflections in the flow around the particles and in some cases the catalyst surface is not evenly used. Sometimes. In general, there is interest in using monoliths when performing catalytic processes that use a large volume flow and set up adiabatic reactions at high temperatures. These characteristics apply to chemical production techniques, especially to dehydrogenation reactions that proceed in the temperature range from 400 ° C to 700 ° C.

  Advances in catalyst technology allow the dehydrogenation reaction hydrogen to be selectively burned in the presence of hydrocarbons, for example, as described in US Pat. No. 7,034,195. Such a mode of operation is called autothermal dehydrogenation, which allows the dehydrogenation reactor to be heated directly, eliminating the need for cumbersome equipment to indirectly preheat or intermediately heat the reaction mixture. Become. Such a technique is described in, for example, US Patent Application Publication No. 2008/0119673. However, this method has a serious drawback that the dehydrogenation reaction is performed in a heterogeneous catalyst in the form of a pellet. That is, since the flow resistance of the bulk material in the form of pellets is high, the cross section of the reactor must be enlarged, and accordingly, the flow rate must be slowed to suppress the pressure drop in the catalytically active layer. This disadvantage is offset by the use of a very costly oxygen metering and distribution device, but this hinders the advantages of autothermal dehydrogenation.

EP-A-2506963 discloses a method for receiving a mixed reaction gas in a heterogeneous catalyst configured as a monolith and performing autothermal gas phase dehydrogenation of a hydrocarbon-containing gas stream using an oxygen-containing gas stream. A horizontal cylindrical reactor is disclosed, in which the reactor
A housing G which is detachably arranged in the longitudinal direction of the reactor, and is sealed by a cylindrical or prismatic housing G which is hermetically sealed in the circumferential direction and open at both end faces. The internal space of the vessel is
An inner region A having one or more catalytically active areas each provided with a plurality of monolithic packages stacked vertically and horizontally
-It is divided into the inner area A and the outer area B arranged coaxially, and upstream of each catalytic activity area is provided with a mixing area having fixed contents, respectively.
A carbon-containing gas stream to be dehydrogenated is introduced into the outer region B, the hydrocarbon stream to be dehydrogenated is deflected at the end of the reactor, and the inner region A is passed through a rectifier One or more supply channels for supplying to
One or more independently adjustable supply paths for supplying an oxygen-containing gas stream to the respective mixing zones, each supply path supplying one or more distribution chambers, respectively. One or more supply channels, and
An outlet path for flowing out the reaction mixture of the autothermal vapor phase dehydrogenation at the end of the reactor, the same outlet as the supply path for supplying the hydrocarbon stream to be dehydrogenated It has a road.

  The reactor end portion in which the outlet path for allowing the reaction gas mixture of the autothermal vapor phase dehydrogenation to flow is arranged is advantageously provided with a tube group type heat exchanger having a tube group, A reaction gas mixture for performing autothermal vapor phase dehydrogenation is guided in the tube group, and spaces are provided between the tubes of the tube group. A hydrocarbon-containing gas stream to be dehydrogenated is flowed in a direction opposite to the flow of the dehydrogenation reaction gas mixture.

  WO 2012/084609, based on EP 2506963, describes an improved reactor in terms of safety technology, in which the outer region B A gas that is inert under the reaction conditions of the autothermal vapor phase dehydrogenation is supplied, and the hydrocarbon-containing gas stream to be dehydrated and treated is introduced into the heat exchanger via the supply path, thereby mixing the reaction gas. The gas is heated by indirect heat exchange in the reverse flow direction and further sent to the terminal end of the reactor opposite to the heat exchanger, where the direction of the reaction gas mixture is changed and the reaction is performed. The gas mixture flows into the inner region A via the rectifier and is mixed with the oxygen-containing gas stream in the mixing zone, thereby generating an autothermal vapor phase dehydrogenation reaction in the inner region A of the reactor.

  However, the structure of the above reactor is complicated. This is particularly due to the fact that the space inside the reactor is divided into an inner region and an outer region where the housing is arranged in the longitudinal direction of the reactor.

  In view of the above points, an object of the present invention is a reactor for performing autothermal vapor phase dehydrogenation using a heterogeneous catalyst configured as a monolith, and has a configuration that is significantly simplified from the above publication. And to realize a reactor that guarantees that the monolith can be easily exchanged if necessary.

The solution to the problem is a cylindrical shape for receiving a reaction gas mixture in a heterogeneous catalyst configured as a monolith and performing autothermal vapor phase dehydrogenation of a hydrocarbon-containing gas stream using an oxygen-containing gas stream. A reactor wherein the longitudinal axis of the cylinder is longitudinal;
One or more catalytically active zones are provided in the internal space of the reactor, each catalytically active zone having a package consisting of a plurality of monoliths stacked laterally and / or longitudinally, A mixing zone with fixed contents is provided upstream of each catalytic activity zone,
One or more supply paths for the hydrocarbon-containing gas stream to be dehydrogenated are provided at the lower end of the reactor,
One or more independently adjustable supply paths for supplying an oxygen-containing gas stream to the respective mixing zones, each supply path supplying one or more distributors, respectively. One or more supply channels are provided,
One or more outlet passages for the reaction gas mixture of the autothermal gas phase dehydrogenation are provided at the upper end of the reactor;
An insulating layer is provided on the entire inner wall of the reactor,
It is ensured that the one or more catalytic activity zones can be accessed from outside the reactor via one or more manholes, respectively;
Or
Each of the one or more catalytically active areas is
-Said mixing zone with fixed contents provided upstream from each catalytic activity zone;
One or more supply paths that are adjustable independently of each other;
One or more distributors each supplied by one supply channel, including the one or more distributors, each configured as an individually removable part, and / or Alternatively, the reactor includes a package composed of a plurality of monoliths stacked vertically.

  The individual parts can be joined and separated from each other, for example via a welded seam.

  In particular, flanges can be used to couple and separate the individual parts from each other.

In one embodiment, the problem is a cylindrical shape for receiving a mixed reaction gas in a heterogeneous catalyst configured as a monolith and performing autothermal gas phase dehydrogenation of a hydrocarbon-containing gas stream using an oxygen-containing gas stream. The longitudinal axis of the cylindrical shape is the longitudinal direction,
One or more catalytically active zones are provided in the internal space of the reactor, each catalytically active zone having a package consisting of a plurality of monoliths stacked laterally and / or longitudinally, A mixing zone with fixed contents is provided upstream of each catalytic activity zone,
One or more supply paths for the hydrocarbon-containing gas stream to be dehydrogenated are provided at the lower end of the reactor,
One or more independently adjustable supply paths for supplying an oxygen-containing gas stream to the respective mixing zones, each supply path supplying one or more distributors, respectively. One or more supply channels are provided,
One or more outlet channels for the reaction gas mixture of the autothermal gas phase dehydrogenation are provided at the upper end of the reactor,
Each of the one or more catalytically active areas can be accessed from the outside of the reactor through one or more manholes, respectively, and an insulating layer is provided on the entire inner wall of the reactor.

  Accordingly, the present invention provides a cylindrical reactor whose longitudinal direction is the longitudinal direction, that is, a reactor configured as an upright apparatus.

  The monolith is assembled in the catalytic activity zone so that the flow in the monolith passageway is longitudinal.

  Autothermal gas phase dehydrogenation is carried out in a heterogeneous catalyst in the form of a monolith.

Here, the monolith is a unitary parallelepiped block having a large number of through passages arranged in parallel with each other, and each passage has a small cross section of about 0.36 mm ² to 9 mm ^2. Point to. The passage is preferably formed to have a square cross section, in particular the length of one side of the square is in the range from 0.6 mm to 3 mm, particularly preferably from 1.0 mm to 1 mm. Within the range of up to 5 mm.

  Said monolith advantageously consists of a catalytically active layer deposited on a ceramic material as support material, preferably by the so-called washcoat method.

A commonly used material for monolith structures is cordierite (a ceramic material composed of magnesium oxide, silicon oxide and aluminum oxide, the ratio is 2: 5: 2). Other materials that are commercially available in monolithic structures are metals, mullite (a mixed oxide in which silicon oxide and aluminum oxide are mixed in a ratio of 2: 3) and silicon carbide. The specific surface area of these materials (BET = Brunauer, Emmet and Teller) is as small as cordierite (eg, the specific surface area of cordierite is typically 0.7 m ² / g).

  Monolithic ceramic members are available with a cell density of 25-1600 cpsi (corresponding to the number of cells per square inch, cell size of 5-0.6 mm). Using a higher cell density increases the geometric surface area and allows the catalyst to be used more efficiently. The disadvantages of high cell density are that the manufacturing process is somewhat difficult, washcoat deposition is more difficult, and the pressure loss in the reactor is high. In addition, cell walls typically become thinner as the cell density increases, thereby reducing the mechanical stability of the monolith. In a cylindrical reactor, the monolith edge region must be adjusted by cutting appropriately. However, for monoliths with a high cell density, the pressure loss is very small compared to packed reactors (usually 1/10). This is due to the monolithic passage being straight.

  In order to manufacture a monolithic ceramic member, a mixture of talc, clay, a component supplying aluminum oxide, and silicon dioxide is manufactured, the mixture is mixed to form a molding material, the mixture is formed, The raw material can be dried and heated at temperatures from 1200 ° C to 1500 ° C. In this way, a ceramic mainly containing cordierite and having a low coefficient of thermal expansion is obtained. In general terms, a monolithic carrier can be formed by extruding a paste having the appropriate rheological properties and the appropriate composition. This paste usually contains ceramic powder of appropriate particle size, inorganic and / or organic additives, solvent (water), peptizer (acid) for adjusting the pH value, permanent binder agent (colloid solvent or Sol). The additive may be a plasticizer or surfactant for adjusting the viscosity of the paste, or may be a temporary binder that can be incinerated later. Sometimes glass fibers or carbon fibers are added to improve the mechanical strength of the monolith. The permanent binder agent should improve the internal strength of the monolith.

Cordierite monoliths can be made from raw materials consisting of talc, kaolin, calcined kaolin, and aluminum oxide, thereby providing 45 to 55 wt% SiO ₂ and 32 to 40 wt%. % Of Al ₂ O ₃ and 12% to 15% by weight of MgO are produced together. Talc is a material mainly composed of magnesium hydroxide silicate Mg ₃ Si ₄ O ₁₀ (OH) ₂ . Talc is tremolite (CaMg ₃ (SiO ₃ ) ₄ ), serpentine (3MgO.2SiO ₂ , 2H ₂ O), anthophyllite (Mg ₇ (OH) ₂ (Si ₄ O ₁₁ ), depending on the mining source and purity. ₂ ), magnesite (MgCO ₃ ), mica, and other minerals such as chlorite.

Other materials such as SiC, B ₄ C, Si ₃ N ₄ , BN, AlN, Al ₂ O ₃ , ZrO ₂ , mullite, aluminum titanate, ZrB ₂ , sialon, perovskite, carbon and TiO ₂ by extrusion molding It is also possible to produce a monolith from

Important with respect to the properties of the monolith product are the quality of the nozzle during extrusion, the type and characteristics of the material used to produce the moldable mixture, as well as the additive added, pH value, moisture content, and This is the force used during extrusion. Additives used at the time of extrusion are, for example, cellulose, CaCl ₂ , ethylene glycol, diethylene glycol, alcohol, wax, paraffin, acid and heat-resistant inorganic fibers. In addition to water, it is also possible to use other solvents such as ketones, alcohols and ethers. By adding additives, it is possible to improve the characteristics of the monolith, such as microcrack formation, thereby improving temperature change resistance, improving porosity, improving absorption performance, and The mechanical strength can be improved, or the thermal expansion can be reduced.

  This bare monolith structure is coated with a catalyst carrier layer containing one or more ceramic oxides, or the catalytic metal and any other (promoting) elements are already ceramic oxides. A catalyst layer containing a material supported on a support material is coated. This coating treatment is formed by a wash coat film forming method.

  In the following, advantageous embodiments for assembly into the reactor will be described in detail.

Embodiment 1:
In the reactor, a plurality of monoliths are stacked so as to contact each other in the horizontal direction and the vertical direction without leaving a space. In that case, it must be ensured that all monoliths flow vertically.

  For reasons of manufacturing technology, monoliths have irregularities and distortions, and therefore, when they are stacked, the widths of the gaps formed between the adjacent monoliths are different. This creates a detour of the reaction gas mixture. Therefore, it is necessary to apply a catalyst coating to the outer wall of the monolith.

  The monolith must be adjusted according to the cylindrical inner wall of the reactor by cutting according to the curved surface of the reactor. Preferably this cut is already made before delivery of the monolith for assembly into the reactor. This is because, in this way, incidentally generated dust and residue can be directly supplied to precious metal recycling.

  Monoliths can be assembled directly over one or more layers without any spacing, or they can be offset from each other. 5 to 30 layers are preferably assembled one on the other, in particular 15 to 20 layers are assembled one on the other.

  In one advantageous embodiment, the layers are arranged and assembled with a rotational offset of 45 ° relative to each other so that a continuous through gap is not created in the package. Said layer is advantageously provided in such a way that the corner points of the monolith of the next layer rest on the point where the four monoliths are adjacent to each other in the layer below it.

For assembling the lateral layers, it is advantageous to proceed in the following manner:
First, a suitably cut frame member is attached to the inner shell of the reactor, and then each monolith is introduced from the outside to the inside. The last four monoliths that fill the middle of the layer are inserted together, and the last four monoliths are inserted once more firmly into the other remaining monoliths of the layer, towards the reactor inner wall in the edge region Push into mat seal.

  In the above-described embodiment, it becomes difficult to assemble the temperature monitoring element. This is because the temperature monitoring element has a thickness larger than the passage width of the monolith due to manufacturing, and this impedes the flow in the monolith. However, there is a means in which a temperature monitoring element is separately assembled in each gap between each monolith, the temperature monitoring element is drawn out into the expansion mat sealing portion toward the outside, and is connected to the outside of the reactor from here through the port. is there. As another mode for assembling the temperature monitoring element, there is a mode in which a through hole is formed in a monolith, a thermal sleeve is inserted, and then a multi-thermocouple is assembled in the thermal sleeve.

Embodiment 1a:
In the following embodiments, a thermocouple can be easily assembled for temperature monitoring without blocking the monolith passage. In order to do this, the monolith is assembled as described in the first embodiment, and in that case, a thin metal plate spacer is inserted to ensure a space between the layers directly overlapping in the vertical direction. The thin metal plate spacers are assembled, for example, in the form of a grid or assembled as individual parts. In this way, it is ensured that there is an interval in the range of 10 mm to 50 mm, preferably an interval in the range of 10 mm to 20 mm, between the monolith layers that overlap each other.

Embodiment 2:
Embodiment 2 corresponds to embodiment 1a. That is, in this aspect, a plurality of lateral layers of monoliths are provided, and these layers are assembled with each other at intervals with a spacer. This embodiment 2 is different from embodiment 1a in that the monoliths of the respective layers are sealed with each other by being inserted into the expansion mat or the mineral fiber nonwoven mat on the side where the reaction gas mixture does not flow. It is that you are.

Embodiment 3:
Embodiment 3 is premised on a module of two or more monoliths that are overlapped in the horizontal and / or vertical direction, and this monolith module can still be assembled in the reactor via a manhole (ingress port). The dimensions must be adjusted. The peripheral surface of each module is wrapped in a mineral fiber nonwoven fabric or in an expanded mat, preferably made of ceramic fibers made of polycrystalline mullite fibers, by opening through holes for flowing the reaction gas mixture in the monolith passages, Insert into the metal casing using fasteners. The modules are arranged in the horizontal direction, and as described in the embodiment 1a, the metal plate spacers are inserted, and the modules are arranged so as to overlap each other in the vertical direction.

  The reactor operates at a temperature between 500 ° C. and 690 ° C., preferably at a temperature between 550 ° C. and 620 ° C., and the flow through the reactor takes place from below to above. During reactor operation, the metal reactor sleeve expands more than the ceramic monolith and can loosen.

  Therefore, in the present invention, a region having a monolith on the inner wall of the reactor is covered with a pressure-resistant insulating portion, and the monolith is sealed from the pressure-resistant insulating portion using an expansion mat.

  The advantage of applying an insulating coating to the inner wall is that the temperature of the reactor wall is lowered, thereby reducing the thermal expansion of the reactor wall. Furthermore, since the reactor temperature decreases, a low-cost material can be selected for the reactor shell, and the sealing performance that the expansion mat should exhibit in the edge region can be suppressed.

  In the monoliths of embodiments 1 and 1a, the entire surface must be coated, i.e. both in the passageway and in the monolith outer surface.

  The macroporous structure of the ceramic monolith makes it easy to fix the washcoat layer. The method of film formation of the washcoat can be divided into two methods. The macroporous support (part) can be filled with a washcoat material having a large surface area, or the washcoat can be used as a layer to form a ceramic support. A film can be formed in the pores. By filling the pores in this way, the interaction between the monolith and the washcoat is maximized. This is because most of the washcoat layer is actually fixed in the pores of the carrier and is not bonded only to the outer surface of the monolith passage. Such a film forming method is performed using a solution (or sol) in which a material to be deposited is dissolved, or using a solution containing very small colloidal particles. A drawback of coatings using pore filling is that the amount of coating that can be deposited is limited. This is because the pores will eventually be completely filled, making it impossible to contact the washcoat.

  Monoliths provide advantageous preconditions for carrying out the autothermal dehydrogenation of hydrocarbons, in particular the reactor cross-section is narrow compared to an irregularly packaged fixed bed, and the flow rate It is possible to realize a high speed of oxygen, and thereby, it becomes possible to meter the oxygen efficiently and stepwise into the mainstream containing hydrocarbons. In this way, both the mechanical load on the distributor and the mechanical load on the fixed contents of the mixing zone are reduced due to the smaller reactor cross section compared to the irregularly packed fixed bed. Becomes smaller. That is, when the fixing length is shortened, the adhesion durability of the fixed contents in the distributor and the mixing area is weakened. Further, the main flow direction in the reactor is not limited to the downward direction as in the case of an irregularly packaged fixed bed.

If the stop time becomes longer, the catalyst recommended in the publication can usually be easily regenerated after that time. For this regeneration, for example, in the first regeneration stage, the air diluted with nitrogen and / or water vapor (advantageously) at an inlet temperature of 300 ° C. to 600 ° C. (in the extreme case, Flow in a fixed catalyst bed (even at up to 750 ° C). The inlet temperature is often from 500 ° C to 600 ° C. Deposit amount to the catalyst by the regeneration gas can be as much as 10,000 h ^-1 from (based on the total amount of the catalyst after being reproduced) example ^{50h -1,} the oxygen content of the regeneration gas 0.5 volume % To 20% by volume.

  Thereafter, generally using pure hydrogen molecules or otherwise diluted with an inert gas (preferably water vapor and / or nitrogen), otherwise under the same conditions It is recommended to regenerate (hydrogen content must be 1% by volume or more).

  A plurality of monoliths that are stacked in the transverse and longitudinal directions to form a package are preferably wrapped in an expanded mat or a mineral fiber nonwoven and inserted into the casing using fasteners. It is preferable to use a non-woven fabric such as a non-woven fabric known as an exhaust gas catalyst as the mineral fiber non-woven fabric. For example, it is advantageous to use Interlam (registered trademark) which is a support mat of 3M (registered trademark). It is.

  Expansion mats are known in the field of catalytic exhaust gas cleaning and are described, for example, in DE 40 26 666 A1. The expansion mat described here basically consists of ceramic fibers embedded with mica, such as vermiculite, among others. By embedding mica, it becomes difficult for the expansion mat to expand when the temperature rises, and this makes it possible to hold the object wrapped in the expansion mat particularly reliably when the temperature rises.

  Mineral nonwovens or inflatable mats expand in response to heat and seal the monolith, usually ceramic, from the housing, in particular the friction of the monolith in the housing and the reaction gas mixture on the inner wall of the housing. Is selected to prevent detouring and flow.

  The monolith can be stably positioned by means of an inflatable mat in the edge area that encloses the monolith. This is because monoliths produce tension when thermally expanded. However, if used in the wrong usage, this tension may ease over time. It is therefore advantageous to provide a fastener.

  A package consisting of a plurality of monoliths stacked laterally and / or longitudinally can advantageously be composed of four or more partial packages, each of which has a separate metal surface. And the partial packages can be assembled such that these partial packages completely fill the cross section of the reactor and can be sealed to each other with respect to the bypass path. Yes.

  Instead of the above embodiment, or in combination with the above embodiment, it is possible to assemble a package composed of two or more partial packages at the height.

  Preferably, all of the partial packages described above can be combined in one housing for ease of handling.

  Packages consisting of monoliths stacked in the horizontal and / or vertical direction are arranged, inter alia, on one grid stand.

  The grid base should advantageously be constructed so as not to block the passage for the reaction gas mixture to flow. In order to reliably prevent this, it is advantageous to make the cross section of the monolith passage of one or more layers provided in the area directly in contact with the grid base more than the cross section of the other monolith with a greater distance to the grid base. It is to make it much larger. The thickness of the partition between the passages must be thin so that the upper passage is not blocked by the partition.

  Alternatively, one or more layers of wire mesh can be provided on the lattice base. In that case, the mesh of the layer arranged directly on the lattice base is made somewhat coarser, and the mesh closer to the monolith is made finer. Advantageously, the mesh width is from 5 mm to 15 mm and the wire diameter is from 0.2 mm to 2 mm.

  In combination with the above-described embodiment or alternatively, in place of the above-described embodiment, a layer made of a foamed ceramic with an open hole can be provided in a region in direct contact with the lattice base. The volume of the gap through which the ceramic foam can flow is preferably 70% to 90%.

  Particularly preferably, a first layer made of a high porosity foamed ceramic is provided in a region directly in contact with the lattice platform, and a second layer made of a plurality of monoliths having a thickness of 50 mm can be provided thereon. . The cross section of this second layer passage is larger than the passage cross section of other monoliths with greater distance from the grid base. In particular, the volume of the free gap of the first layer is about 70% and the height of the first layer is in the range from 10 mm to 100 mm, preferably in the range from 40 mm to 60 mm.

  An insulating layer is provided on the entire inner wall of the reactor, that is, completely over the entire length of the reactor.

  In the region of the catalytic active zone, the insulating layer on the inner wall must be pressure resistant and as tight as possible. This insulating layer is preferably constructed in a two-layer structure in the region of the catalytically active zone, facing the pressure-resistant first layer in contact with the inner wall of the reactor and the inner space of the reactor, And a second layer made of an expansion mat.

  Advantageously, another layer made of an expansion mat, which is much thinner than the pressure-resistant layer, is provided between the pressure-resistant layers provided on the inner wall of the reactor, so that the pressure-resistant layer and the inner wall of the reactor are Ensure that contact is as good as possible.

  In other areas of the reactor inner wall, i.e. in the area of the distributor and in the area of the mixing zone, the insulating layer is preferably single-layered and prevents the reaction gas mixture from entering the insulating layer. The metal-coated plate is made of a high-temperature-resistant fiber mat provided on the side facing the inner space of the reactor. The high temperature resistant fiber mat is, in particular, polycrystalline mullite fiber.

  The hydrocarbon-containing gas stream to be dehydrogenated is introduced into the reactor from the lower end of the reactor and flows through the reactor from below to above.

  Advantageously, the hydrocarbon-containing gas stream to be dehydrogenated is preheated. This preheating is advantageously carried out in a heat exchanger which is arranged above the uppermost catalytically active zone in the reactor or arranged outside the reactor. In that case, the hydrocarbon-containing gas stream to be dehydrogenated is introduced into the heat exchanger via the supply path, and indirect heat exchange is performed in the heat exchanger by the reaction gas mixture in the reverse flow direction. And then led to the lower end of the reactor opposite to the heat exchanger where it is redirected and introduced into the reactor via a port and in the mixing zone oxygen Mixed with the containing gas stream, which results in an autothermal gas phase dehydrogenation reaction in the catalytically active zone within the reactor.

  The heat exchanger incorporated in the reactor can be, inter alia, a plate-type heat exchanger or a tube group-type heat exchanger with a reverse flow operation system.

  The tube group heat exchanger is preferably made of special steel with high heat resistance, in particular made of special steel with material number 1.4541 or 1.4910. Both ends of each tube of the tube group heat exchanger are tube plates, preferably without gaps, inserted by back plate welding, and on the high temperature side of the tube plate of the tube group heat exchanger, a heat-resistant special steel In particular, plating is performed using a special steel having a material number of 1.4841. Particularly advantageous is a floating head tube plate type heat exchanger.

  Advantageously, the hydrocarbon-containing gas stream to be dehydrogenated can be introduced into the heat exchanger at two or more locations, advantageously with a higher mass flow and a higher mass flow than the main stream. It can be introduced as one or more side streams with a low flow rate.

  An advantage for starting the reactor is that it allows the heat exchanger to be bypassed.

  Hereinafter, the starting of the reaction system, that is, heating the reaction system to the reaction temperature of the autothermal gas water dehydrogenation will be described.

  Initially the reaction system, i.e. the reactor, heat exchanger and connections are at ambient temperature, this reaction system must be at the operating temperature of autothermal gas water dehydrogenation, butane butane dehydrogenation process The temperature must be about 550 ° C.

  Step 1: Heat the reactor to about 200 ° C.

  The reaction system is heated using a heated gas. This heated gas can be, for example, recycle gas or nitrogen and is supplied at about 230 ° C. via a feed line. At that time, the heat exchanger is short-circuited (bypass connection) on the peripheral surface. That is, the heated gas flows directly into the reactor to heat the reactor to about 200 ° C., then heats it only through the heat exchanger tubes and then flows out of the reaction system. No heated gas flows in the outer shell space surrounding the heat exchanger tubes.

  Step 2: The outer shell space is sufficiently oxygen-free by washing the outer shell space.

  A temperature measuring device is provided at the tube-side outlet of the heat exchanger. As soon as this temperature measuring device shows a temperature of about 200 ° C., the bypass connection of the heat exchanger is stopped, and the heated gas is caused to flow in the reverse direction on the peripheral surface side in the heat exchanger. In this way, the outer shell space is cleaned.

Step 3: The reaction system is further heated by burning in the reactor using the combustion gas.
The reactor supply path is provided with one or a plurality of combustion gas supply paths, to which a corresponding mixing mechanism is connected downstream. Particularly suitable as the combustion gas is hydrogen, a rare gas, or a hydrocarbon to be dehydrogenated. Particularly advantageous is hydrogen. The hydrogen already ignites in the noble metal-containing catalyst coating when it reaches about 200 ° C. and heats the reactor to the required operating temperature, in particular about 550 ° C. For this purpose, an oxygen-containing stream, lean air, or particularly advantageously air can be supplied as the supply gas. The distance from the combustion gas nozzle injection part to the noble metal-containing catalyst must be as short as possible. In particular, the concentration of the combustion gas used must be limited so that the gas composition in the reaction system is outside the explosion zone, in particular so that it is outside the detonation zone under actual operating conditions. Advantageously, a minimum combustion gas concentration is also set so that the temperature rise realized by combustion at the reactor inlet is sufficient to raise the temperature of the cold feed gas in the regenerative heat exchanger. The minimum combustion gas concentration must be set. When hydrogen is used as the combustion gas, it is particularly advantageous for the hydrogen concentration to be about 1.4% by volume.

  Advantageously, in addition to the heat exchanger, one or more additional heating sections are provided for heating the hydrocarbon-containing gas stream to be dehydrogenated.

  It is particularly advantageous to provide an electric heater as the additional heating part. This electric heater is, inter alia, removably provided as a plug-in heater or a muffle burner in the hydrocarbon-containing gas stream to be dehydrogenated after leaving the heat exchanger.

  The hydrocarbon-containing gas stream flows into the reactor through the port from below and is rectified in each mixing zone with fixed contents upstream from each catalytic activity zone, thereby downstream from the mixing zone. Then, the deviation from the average value is ± 2% at the maximum in the entire cross section of the reactor.

  The oxygen-containing gas stream is fed into each mixing zone via one or more feed channels that can be adjusted independently of each other, each feed channel feeding one or more distributors. .

  Said distributor can in particular be an annular distributor or a parallel rod distributor.

  Since the residence time after the oxygen-containing gas stream has entered the hydrocarbon-containing gas stream must be very short, in particular less than 60 ms, it is advantageous to improve the degree of mixing, for example mixing plates, Additional devices such as elongated or annular metal strips.

  The supply path for the oxygen-containing gas stream is preferably thermally compensated and secured to the reactor wall by a holding piece.

  Advantageously, each mixing zone has its own pipe distributor, each pipe distributor having a number of plug pipes arranged parallel to each other in a plane perpendicular to the longitudinal direction of the reactor. A plurality of mixing members equally spaced from each other, the multiple insertion pipes being in communication with one or more distribution chambers, and being spaced from each other at equal intervals It has a number of outlets for letting the oxygen-containing gas stream out of the inlet pipe.

  It is particularly advantageous that the mixing member is formed as a mixing plate.

  In the present invention, a manhole or access port is provided that is sized to allow an operator to enter the interior space of the reactor, and this manhole is accessible from outside the reactor to each of the plurality of catalytic activity zones. It is for making it possible. This, combined with the upright configuration of the reactor, allows individual access to each catalytic activity zone from outside the device without having to remove a portion of the device. By being able to enter easily through a manhole, it becomes possible to remove and assemble each catalytic activity package and each grid stand corresponding to this individually.

In particular, autocatalytic gas phase dehydrogenation of a hydrocarbon-containing gas stream using an oxygen-containing gas stream by receiving a reaction gas mixture in a heterogeneous catalyst configured as a monolith that can guarantee simple catalyst replacement that saves time. An embodiment of a cylindrical reactor for which the longitudinal axis is longitudinal is to be configured as follows:
One or more catalytically active zones are provided in the internal space of the reactor, each catalytically active zone having a package consisting of a plurality of monoliths stacked laterally and / or longitudinally, A mixing zone with fixed contents is provided upstream of each catalytic activity zone,
One or more supply paths for the hydrocarbon-containing gas stream to be dehydrogenated are provided at the lower end of the reactor,
One or more independently adjustable supply paths for supplying an oxygen-containing gas stream to the respective mixing zones, each supply path supplying one or more distributors, respectively. One or more supply channels are provided,
One or more outlet channels for the reaction gas mixture of the autothermal gas phase dehydrogenation are provided at the upper end of the reactor,
The inner wall of the reactor is entirely provided with an insulating layer and is not provided with a manhole for accessing each of the one or more catalytically active areas, but is stacked in the horizontal and / or vertical direction. Each of the one or more catalytically active areas, each containing a package consisting of a plurality of monoliths, can be adjusted independently of the mixing area with fixed contents provided upstream of each catalytically active area The one or more supply paths and the one or more distributors, respectively, together with the individually removable parts, ensure that each of the one or more catalytic activity zones can be accessed. ing.

  In the embodiment, for example, when the individual parts need to be removed due to catalyst deactivation, the individual parts are individually and completely fully separated, in particular by loosening the corresponding flanges individually. Can be removed. The only further work required is to remove the necessary fittings and measuring and adjusting devices. Accordingly, after replacing the monolith constituting the catalyst or the monolith containing the catalyst, the individual parts can be easily reinstalled.

  In the said embodiment, preparation time can be shortened to 1/10 of the reactor of the same kind with which attachment is performed via a manhole.

  In addition, by omitting the manhole, the space without catalyst between successive monolith packages can be significantly reduced, so a smaller reactor with the same capacity can be constructed, and By reducing the volume of the space where there is no catalyst, the residence time of the reaction gas mixture in the space is also shortened. Such an advantage is achieved because an uncontrollable side reaction does not occur or the scale at which the side reaction occurs is significantly reduced.

  The present invention is further directed to a method for performing autothermal vapor phase dehydrogenation using the reactor.

  Preferably, two or more reactors are used, and when at least one reactor is used for autothermal gas phase dehydrogenation, at least one other reactor is regenerated at the same time.

  Advantageously, the autothermal gas phase dehydrogenation may comprise dehydrogenating propane, butane, isobutane and butene to produce butadiene, or dehydrogenating ethylbenzene to produce styrene, or ethane. Is dehydrogenated to produce ethylene.

  Since the reactor wall is cylindrical, the reactor of the present invention can be technically easily realized, and circular plates can be used at both ends of the cylindrical reactor wall. Is simple and low cost. This allows the reactor to be configured economically to withstand pressure surges.

  By providing an insulating layer on the entire inner wall of the reactor shell, the demands placed on the material used to manufacture the reactor shell can be relaxed, thereby affecting the material. Cost can be reduced.

  The present invention will be described below with reference to the drawings.

1 is a schematic diagram of a reactor of an advantageous embodiment of the present invention. FIG. 2A shows a reactor incorporating a heat exchanger according to another advantageous embodiment of the invention, and FIG. 2A is a detail view. FIG. 4 shows a reactor with an apparatus for heating using a bypass path on the peripheral surface of the heat exchanger according to another advantageous embodiment of the invention. FIG. 3 shows a reactor with a heat exchanger arranged longitudinally outside the reactor according to another embodiment of the invention. FIG. 4 shows a reactor with a heat exchanger arranged laterally outside the reactor according to another embodiment of the invention. FIG. 2 shows a portion of a reactor of one advantageous embodiment of the invention. 7A and 7B are schematic views of a reactor according to an embodiment of the present invention comprising a plurality of individual parts that are connected to each other by a flange and flow the reaction mixture from below to above, and FIGS. is there. FIG. 8 is a schematic view of a reactor according to an embodiment of the present invention, which is a reactor similar to that of FIG. 7, but in which a reaction mixture is allowed to flow from the top to the bottom. FIG. 8 is a schematic view of a reactor according to an embodiment of the present invention in the same embodiment as in FIG. 7, in which heat exchangers are arranged vertically in the outside of the reactor.

  In the drawings, the same reference numerals indicate the same or corresponding components.

  The schematic diagram of FIG. 1 shows a reactor 1, and a hydrocarbon-containing gas stream 2 is supplied to the reactor 1 via a supply path 7 at the lower end of the reactor 1. A gas stream 3 containing oxygen is introduced into each mixing zone 6 via a supply channel 9. A catalytically active area 5 is connected to each of the mixing areas 6, and each catalytically active area 5 is composed of a plurality of monoliths 4 stacked in the horizontal direction and the vertical direction. The reaction gas mixture flows out of the reactor through the port 11 at the upper end of the reactor.

  The embodiment shown in FIG. 2 is different from the embodiment shown in FIG. 1 in that a heat exchanger is incorporated in the upper end portion of the reactor 1.

  In the detail view of FIG. 2A, the technical elements of one catalytically active zone 5 are shown, together with the supply path 9 and the manhole 12 for the oxygen-containing gas stream 3. The manhole 12 is used to ensure access to the monolith of the package in the catalytic active area 5.

  The embodiment shown in FIG. 3 further includes an apparatus for heating the reaction system to the operating temperature using a bypass path on the circumferential surface of the heat exchanger 17.

  The heated gas 20 first flows upward from the bottom through the inside of the reactor 1, and then flows into the pipe of the heat exchanger 17. As soon as the temperature of the gas stream flowing out from the upper end of the reactor reaches about 200 ° C., the bypass of the heat exchanger 17 is stopped and the heated gas also flows into the casing space of the heat exchanger. A heat exchanger 21 is additionally provided in the heating gas supply pipe to the reactor 1. In order to further heat the reaction system, the combustion gas 22 is introduced at the lower end of the reactor 1 via the mixing device 23.

  FIG. 4 is a view showing a reactor 1 including a heat exchanger 17 arranged in a vertical direction laterally outside the reactor 1 according to another embodiment of the present invention.

  FIG. 5 is a view showing a reactor provided with a heat exchanger 17 disposed laterally laterally outside the reactor 1 according to another embodiment of the present invention.

  The excerpt of FIG. 6 shows a configuration in which an insulating layer is provided on the inner wall of the reactor. This insulating layer is provided in a two-layer structure in the region of the catalytically active area 5, one of which is a first layer 13 made of a pressure-resistant material in contact with the inner wall of the reactor, and the other layer is A second layer facing the inner space of the reactor, consisting of an expansion mat.

  In other regions, an insulating layer 15 having a single layer structure is provided. This one insulating layer 15 is made of a fiber mat and is provided with a metal-coated plate on the side facing the inner space of the reactor.

  This excerpt shows that the oxygen-containing gas stream 3 is supplied via a distributor 10, which has a number of plug pipes 19 arranged in the longitudinal direction of the reactor. Consists of.

  In addition, the lattice base 16 is also shown in FIG.

  The reactor of one embodiment of the present invention shown in FIG. 7 has a configuration having three individually removable parts 24 as an example, and FIG. 7A is a diagram showing details of the intermediate part 24. FIG. 7B shows details of the lower part 24.

  The reactor 1 shown in FIG. 8 has the same configuration as that of the reactor 1 of FIG. 7, but the flow direction of the reaction mixture is reversed, and accordingly, the arrangement of the supply path 9 of the oxygen-containing gas stream 3 is also changed. It has changed.

  Both reactors 1 shown in FIGS. 7 and 8 are composed of a plurality of parts 24 that can be individually attached and detached.

  The reactor 1 shown in FIG. 9 corresponds to the reactor 1 shown in FIG. 3, but is not provided with a manhole for accessing the monolith, and each individual component 24 can be removed using the flange 25. Are connected to each other.

1 Reactor 2 Hydrocarbon-containing gas stream 3 Oxygen-containing gas stream 4 Monolith (s) 5 Catalytic activity zone 6 Mixing zone 7 Gas stream 2 feed path 8 Outer insulation 9 Gas stream 3 feed path 10 Distribution 11 Exit channel 12 Manhole 13 Shape stability insulating part 14 Sealing part 15 Protective insulating part 16 Grid base 17 Heat exchanger 18 Port 19 Plug pipe 20 Heating gas 21 Additional heat exchanger 22 Combustion gas 23 Mixing device 24 Parts 25 Flange

Claims (20)

In order to obtain a reaction gas mixture via a heterogeneous catalyst configured as a monolith (4) , autothermal gas phase dehydrogenation of the hydrocarbon-containing gas stream (2) using the oxygen-containing gas stream (3) is performed. A cylindrical reactor (1) for carrying out, the longitudinal direction of which is the longitudinal direction,
One or a plurality of catalytically active zones (5) are provided in the internal space of the reactor (1), each of the catalytically active zones (5) being respectively superposed in the horizontal and / or vertical direction And a mixing zone (6) having a fixed content, respectively, upstream from each catalytic activity zone (5),
- the the lower end of the reactor (1), and one or more of the supply paths for the dehydrogenation process the hydrocarbon-containing gas stream of the subject (2) (7) is provided,
One or more feed paths (9) adjustable independently of each other for feeding the oxygen-containing gas stream (3) to the mixing zones (6), each feed path ( 9) supplied by each of the one or more distributors to (10), and one or more supply channel (9) is provided,
- the the upper part of the reactor (1), wherein is one for the reaction gas mixture of the own thermal vapor dehydrogenation or more outlet passages (11) is provided,
An insulating layer (13, 14, 15) is provided on the entire inner wall of the reactor (1) ,
Or having access to A) their respective one or the external of the reactor plurality of through manhole (12) one or more of the catalytically active zone (5) is guaranteed,
Or
B) wherein one or more of the catalytically active zone (5), from each catalytic active area (5) provided upstream, the mixing zone having a fixed content and (6), mutually independent it is adjustable without the one or more supply passages (9), together with their respective one supply channel (9) wherein one or more distributors are supplied by (10), the individual constitute a component (24) is removable, the
A reactor (1) characterized in that. The parts (24) are individually removable using flanges (25).
Reactor (1) according to claim 1. One or a plurality of catalytically active zones (5) are provided in the internal space of the reactor (1), each of the catalytically active zones (5) being respectively superposed in the horizontal and / or vertical direction And a mixing zone (6) having a fixed content, respectively, upstream from each catalytic activity zone (5),
- the the lower end of the reactor (1), and one or more of the supply paths for the dehydrogenation process the hydrocarbon-containing gas stream of the subject (2) (7) is provided,
One or more feed paths (9) adjustable independently of each other for feeding the oxygen-containing gas stream (3) to the mixing zones (6), each feed path ( 9) supplied by each of the one or more distributors to (10), and one or more supply channel (9) is provided,
- the the upper part of the reactor (1), wherein is one for the reaction gas mixture of the own thermal vapor dehydrogenation or more outlet passages (11) is provided,
Each of the one or more catalytic active areas (5) is accessible from the outside of the reactor (1) via one or more manholes (12), respectively, and the inner wall of the reactor (1) Are provided with insulating layers (13, 14, 15) on the whole,
Anti応器of claim 1, wherein (1). The insulating layer (13, 14, 15) has a two-layer structure in the region of the catalytic active zone (5), and is a pressure-resistant first layer (in contact with the inner wall of the reactor (1)). 13) and a second layer (14) consisting of an expansion mat facing the internal space of the reactor (1),
The insulating layer (13, 14, 15) is a single layer structure in other regions, and consists of a high temperature resistant fiber mat (15) having a metallized plate on the side facing the internal space of the reactor. ,
Reactor (1) according to any one of claims 1 to 3. The package consisting of the monolith (4) stacked in the horizontal and vertical directions is placed on a grid stand (16),
The area of the monolith (4) having a passage having a larger cross section compared to the cross section of the passage of another monolith (4) farther away from the lattice base (16) is located in the region directly in contact with the lattice base (16). One or more layers are provided,
Reactor (1) according to any one of the preceding claims. In the area directly in contact with the lattice platform (16), a layer made of foam ceramic with open holes is provided,
The pore volume through which the ceramic foam can flow is 70% to 90%.
Reactor (1) according to any one of the preceding claims. In the region in direct contact with the lattice platform (16), a first layer made of foam ceramic with open pores with high porosity is provided,
The first layer is in the range of 10 mm to 100 mm;
Above the first layer is a second layer of monolith (4) having a passage with a larger cross section compared to the cross section of the passage of the other monolith (4) that is further away from the grid (16). Provided,
Reactor (1) according to claim 5 or 6. A heat exchanger (17) is provided above the uppermost catalytic activity zone (5) or outside the reactor (1),
The hydrocarbon-containing gas stream (2) to be dehydrogenated is introduced into the heat exchanger (17) via a supply path (7), and the reaction in the reverse flow direction is performed in the heat exchanger (17). Heated by indirect heat exchange with the gas mixture, further led to the lower end of the reactor (1) and introduced into the reactor (1) via the port (18) at the lower end, The autothermal vapor phase dehydrogenation takes place in the reactor (1) by mixing with the oxygen-containing gas stream (3) in the mixing zone (6).
Reactor (1) according to any one of the preceding claims. The heat exchanger (17) is detachable using a flange (25).
Reactor (1) according to claim 8. The hydrocarbon-containing gas stream (2) to be dehydrogenated is introduced into the heat exchanger (17) at two or more locations;
Reactor (1) according to any one of the preceding claims. The hydrocarbon-containing gas stream (2) to be dehydrogenated is introduced into the heat exchanger (17) as a main stream having a higher mass flow rate and one or more substreams having a lower mass flow rate than the main flow. To be
Reactor (1) according to claim 10. In addition to the heat exchanger (17), one or more additional heating sections for heating the hydrocarbon-containing gas stream (2) to be dehydrogenated are provided.
Reactor (1) according to any one of claims 8 to 11. An electric heater is provided as the additional heating unit,
Reactor (1) according to claim 12. The electric heater is detachably provided in the hydrocarbon-containing gas stream (2) to be dehydrogenated after exiting the heat exchanger (17) as an insertion method or a muffle burner.
Reactor (1) according to claim 13. In the reactor (1), two or more catalytic active zones (5) are provided, each having a package consisting of a plurality of monoliths (4) stacked in the transverse and longitudinal directions,
Reactor (1) according to any one of the preceding claims. Within the same catalytic activity zone (5), each monolith (4) is configured to have a different catalytic activity,
Reactor (1) according to any one of the preceding claims. Two or more of each of the catalytically active zone (5) is configured to have a different catalytic activity,
Reactor (1) according to claim 15 or 16. A plurality of monoliths (4) that are stacked in the transverse direction and the longitudinal direction to form a package are wrapped in an expansion mat or a mineral fiber nonwoven fabric and assembled in a casing using a fastener,
Reactor (1) according to any one of the preceding claims. Each mixing zone (6) has its own pipe distributor,
Each tubular distributor is
A plurality of insertion pipes (19) arranged parallel to each other in a plane perpendicular to the longitudinal direction of the reactor (1);
It consists of a plurality of mixing members arranged at equal intervals from each other,
The plurality of plug-in pipes (19) communicate with one or more distribution chambers;
The plurality of insertion pipes (19) have a plurality of outlets for letting out the oxygen-containing gas flow (3) from the insertion pipe (19), and the plurality of outlets are equally spaced from each other. Arranged,
Reactor (1) according to any one of the preceding claims. A method for performing autothermal vapor phase dehydrogenation using the reactor (1) according to any one of claims 1 to 19, comprising:
Said autothermal vapor dehydrogenation is
Bed Tan, isobutane, butene by dehydrogenation or generation of butadiene,
Dehydrogenation of ethylbenzene to produce styrene, or
A method comprising producing ethene by dehydrogenating ethane.

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